Pica Duellist Build
01-11-2009, 05:32 PM
#27
My Feedback: (67)
Join Date: Nov 2002
Location: lancaster,
CA
Posts: 731
Likes: 0
Received 0 Likes
on
0 Posts
RE: Pica Duellist Build
I just rememberd and Muck can correct me on this, but I think it was he that had posted a shot of his bashed Duellist flying on 1 engine and making a turn. It dispelled some of the rumors that the Duellist automatically becomes a Frisbee when an engine goes out.
01-11-2009, 11:50 PM
#28
Senior Member
Join Date: Feb 2002
Location: Berkeley, CA,
Posts: 215
Likes: 0
Received 0 Likes
on
0 Posts
RE: Pica Duellist Build
Kemo,
Yep, that's the same one I have. Flies absolutely fine with those angles. I'll leave the flight evaluations of the version with zero degree thrust angles, etc, to the pilot/owners of that version.
As Roary correctly recalles, I had an engine out situation that was successfully resolved in the air. Couple things to note however:
1) I have twin fin/rudders that are directly inline with the propwash from each engine, so you can't really consider that unless you do the same. That said, the stock design has ample tail area and if you keep her light (or fly her fast) should have no problems.
2) I kept my auw fairly low (I seem to recall the box indicating 8 pounds - LOL!) which helps keep the stall speed and landing speeds low, as well as makes engine out situations much more manageable.
Build: I found the build to be pretty easy/straight forward. My kit had a fair amount of block balsa for shaping wingtips, noseblock, etc. Hollow them out to keep the weight down!
-E
Yep, that's the same one I have. Flies absolutely fine with those angles. I'll leave the flight evaluations of the version with zero degree thrust angles, etc, to the pilot/owners of that version.
As Roary correctly recalles, I had an engine out situation that was successfully resolved in the air. Couple things to note however:
1) I have twin fin/rudders that are directly inline with the propwash from each engine, so you can't really consider that unless you do the same. That said, the stock design has ample tail area and if you keep her light (or fly her fast) should have no problems.
2) I kept my auw fairly low (I seem to recall the box indicating 8 pounds - LOL!) which helps keep the stall speed and landing speeds low, as well as makes engine out situations much more manageable.
Build: I found the build to be pretty easy/straight forward. My kit had a fair amount of block balsa for shaping wingtips, noseblock, etc. Hollow them out to keep the weight down!
-E
01-12-2009, 03:02 AM
#29
RE: Pica Duellist Build
I built mine 15 years ago as my first twin, third RC plane overall.
O.S. 46's, one of them a counter-rotator. (not sure they make that anymore)
As a relative newbie, the speed of the Duellist spooked me and I didn't fly it much. I built it according to plans, except I put the rudder servo over the CG. (not needed because I then had to add tail weight to balance it). Kit wood was heavy, I glassed it, came in at 11 lbs which spooked me even more because the box said 8 lbs.
Last year, I pulled it out of mothballs on a whim, replaced the standard .46 ( I loaned it to somebody), de-greased the 14 year-old counter-rotator and it flew GREAT! After a few years of flying P-38's, the landings seem docile. I've never heard of a Duellist coming anywhere close to the 8 lbs descrbed on the box. I think it's a myth. If you buy light balsa, make holes in the solid blocks, Monokote it and put servos in the tail so you don't have to add lead, you MIGHT get close to 10 lbs.
With the counter-rotator, it rolls like a bird on a wire....without rudder or elevator input, it just keeps rolling straight till you stop.
With the .55's, it's gonna be really fast!
mt
O.S. 46's, one of them a counter-rotator. (not sure they make that anymore)
As a relative newbie, the speed of the Duellist spooked me and I didn't fly it much. I built it according to plans, except I put the rudder servo over the CG. (not needed because I then had to add tail weight to balance it). Kit wood was heavy, I glassed it, came in at 11 lbs which spooked me even more because the box said 8 lbs.
Last year, I pulled it out of mothballs on a whim, replaced the standard .46 ( I loaned it to somebody), de-greased the 14 year-old counter-rotator and it flew GREAT! After a few years of flying P-38's, the landings seem docile. I've never heard of a Duellist coming anywhere close to the 8 lbs descrbed on the box. I think it's a myth. If you buy light balsa, make holes in the solid blocks, Monokote it and put servos in the tail so you don't have to add lead, you MIGHT get close to 10 lbs.
With the counter-rotator, it rolls like a bird on a wire....without rudder or elevator input, it just keeps rolling straight till you stop.
With the .55's, it's gonna be really fast!
mt
01-16-2009, 01:13 AM
#33
Senior Member
Join Date: Feb 2002
Location: Berkeley, CA,
Posts: 215
Likes: 0
Received 0 Likes
on
0 Posts
RE: Pica Duellist Build
I went with cheap mechanical retracts - each driven by a dedicated retract servo mounted in the back of the engine nacelle.
5/32" music wire stubs with shock absorbing Robo Struts.
I stuck a 12 oz. fuel main tank inside the fuselage aft of the cockpit where the air tank would have gone.
5/32" music wire stubs with shock absorbing Robo Struts.
I stuck a 12 oz. fuel main tank inside the fuselage aft of the cockpit where the air tank would have gone.
01-16-2009, 02:02 PM
#36
My Feedback: (551)
RE: Pica Duellist Build
Mechanical retracts are 100% reliable once they are properly set up. If the radio works, the retracts work and if the radio doesn't work, the retracts don't matter. Pneumatic retracts are subject to running out of air from leaks or just too many cycles. (No, spring-down retracts won't save you in those circumstances. They only lock down if the air loss is instantaneous. Slow loss of air will let them down, but they probably won't lock down, which means that they will fold up on landing.)
Jim
Jim
01-16-2009, 10:43 PM
#37
Senior Member
Join Date: Feb 2002
Location: Berkeley, CA,
Posts: 215
Likes: 0
Received 0 Likes
on
0 Posts
RE: Pica Duellist Build
I used a pair of Futaba's s-136G retract servos (180 degree, non-proportional, high torque).
One of the servos is on a delay circuit so it starts/stops a couple seconds after the other gear starts/stops. This reduces the load on the battery.
Main gear doors cycle open/close during retraction/deployment (they're closed when the gear are up and closed when the gear are down). A smaller forward door remains open, resting on the extended strut leg when the gear are down, and snaps shut when the gear are up.
I haven't tried pneumatic units yet. My experience with mechanicals agrees with Jim's assesment. If they're set up correctly they're 100% reliable with positive up and down locks. No air to leak, no support equipment to bring.
One of the servos is on a delay circuit so it starts/stops a couple seconds after the other gear starts/stops. This reduces the load on the battery.
Main gear doors cycle open/close during retraction/deployment (they're closed when the gear are up and closed when the gear are down). A smaller forward door remains open, resting on the extended strut leg when the gear are down, and snaps shut when the gear are up.
I haven't tried pneumatic units yet. My experience with mechanicals agrees with Jim's assesment. If they're set up correctly they're 100% reliable with positive up and down locks. No air to leak, no support equipment to bring.
01-17-2009, 08:51 AM
#39
Senior Member
RE: Pica Duellist Build
jrf, I can't speak for Robarts, but SpringAir retracts, even with a slow leak, would lock. The internal spring in the actuator is that strong. It would push the over center lock into position. But your slow leak failure causing the gear not to lock down is probably not applicable to a flight. If the leak was at a rate that depleted your air in flight, they would come down when the pressure reached a very low level. If the leak was slow enough that the pressure could still keep the gear retracted, then when you moved the air valve with your gear switch, they would lock down. The only way an air up/spring down gear system would come to earth with gear up is if there was a radio or other system failure and the air valve could not be commanded open. But then these type failures would also affect the other retract systems.
01-17-2009, 10:40 AM
#40
Senior Member
My Feedback: (1)
Join Date: Oct 2002
Location: Yuma Az,Balsam Lake,Wi.,
WI
Posts: 991
Likes: 0
Received 0 Likes
on
0 Posts
RE: Pica Duellist Build
HI have an old one bought built in the 80s I believe.Just freed up the stuck engines and got them to run,Old fox 40,small base I think they call them.Boy are they loud compared to the newer engines!One is the counter rotating apparently they were avaiable from Fox then.Just getting radio set up as it has the old Futaba I even still had some of the adapters for those servos as decided to put in new receiver.Changed to individual throttle servos from the old bellcranks set-upTried the Robarts and they sort of worked went up but little slow coming down but thought pretty good for that many years non-use.Never had them before think did not have enough pressure only pumped to 80Lbs they tell me can go higher?Think won't try them at first just leave locked down enough other things to worry about on it.Looks to be glassed finish never tried weighing it!!About due to get it out and try it!
01-17-2009, 09:30 PM
#41
RE: Pica Duellist Build
Call me Grumpy, but I put fixed landing gear in mine 15 years ago and I haven't been tempted to change it.
I'm sure it would be 10-20% faster in the air with cleaner lines.
But as you know if you've ever flown warbirds (or watched a meet, for that matter), about 80% of the stuff that goes wrong on a plane with retracts has to do with the retracts!
It's a sport plane and, as such, fast enough for me with the gear hangin' out.
mt
I'm sure it would be 10-20% faster in the air with cleaner lines.
But as you know if you've ever flown warbirds (or watched a meet, for that matter), about 80% of the stuff that goes wrong on a plane with retracts has to do with the retracts!
It's a sport plane and, as such, fast enough for me with the gear hangin' out.
mt
01-18-2009, 11:50 PM
#43
Senior Member
Join Date: Feb 2002
Location: Berkeley, CA,
Posts: 215
Likes: 0
Received 0 Likes
on
0 Posts
RE: Pica Duellist Build
I went with a set of very inexpensive Hobbico .60 size mechanicals:
http://www3.towerhobbies.com/cgi-bin...?&I=LXL407&P=0
My Duellist is a tail dragger hence the 2-gear mains.
For just a little more $ they also have a 3 gear set with the stearable nose gear.
They're sized for 5/32" music wire gear legs and they have metal side frames. Since I went with the robo-struts, I just cut a handfull of 2" long strut stubs out of 5/32" music wire. If I botched a landing, all I had to do was swap out the bent 5/32" strut stub. The Robo-struts are pretty bomb proof, at least in my experience.
Like most retracts, if you are prone to hard or bouncy landings, you WILL wear out the end stops and loosen up the bushings.
There's also the Dave Brown set, but I haven't tried them.
http://www3.towerhobbies.com/cgi-bin...?&I=LXL407&P=0
My Duellist is a tail dragger hence the 2-gear mains.
For just a little more $ they also have a 3 gear set with the stearable nose gear.
They're sized for 5/32" music wire gear legs and they have metal side frames. Since I went with the robo-struts, I just cut a handfull of 2" long strut stubs out of 5/32" music wire. If I botched a landing, all I had to do was swap out the bent 5/32" strut stub. The Robo-struts are pretty bomb proof, at least in my experience.
Like most retracts, if you are prone to hard or bouncy landings, you WILL wear out the end stops and loosen up the bushings.
There's also the Dave Brown set, but I haven't tried them.
01-22-2009, 05:33 PM
#46
Join Date: Dec 2005
Location: 19015 PA
Posts: 63
Likes: 0
Received 0 Likes
on
0 Posts
RE: Pica Duellist Build
what are yall using for servos?
mechanical retracts==
rudder==
elevator==
ailerions==
do you think i should put the 2 servos in the rear for elev and rudder to help with weight or at least halfway i do this for my 3d planes ???
i am going with a electric setup powerful one to so i need the room for lipos
thank you so much for yalls help so hows everyones duelist's doing??
mechanical retracts==
rudder==
elevator==
ailerions==
do you think i should put the 2 servos in the rear for elev and rudder to help with weight or at least halfway i do this for my 3d planes ???
i am going with a electric setup powerful one to so i need the room for lipos
thank you so much for yalls help so hows everyones duelist's doing??
